The invention relates to an ultrasound device for sector scanning, which includes an applicator housing for an ultrasound transmission/receiving system and drive and control means. The ultrasound transmission/receiving system consists of an ultrasound transducer head with at least one transducer element. Additionally, the ultrasound transducer head can be swivelled around a swivel axis during specific time intervals to cover a predeterminable angle area.
The sector scan procedure is applied primarily for cardiac examinations. In actual use, ultrasound waves are transmitted and received through the acoustic window located between the ribs (intercostal) and above the collar bone (suprasternal) of a patient. Although many sector scanners are known, technological trends are moving toward the development of compact, and easily operable applicators.
Sector scans can be generated through mechanical or electronic methods. With respect to the mechanical method, an ultrasound transducer head is mechanically swivelled at a given periodic rate. In an electronic method, beam deflection operating according to the "phased array" principle is applied to generate scan areas. Furthermore, mechanically operated ultrasound transducer heads can be tilted by means of an eccentric with an associated push rod mechanism. In yet another mechanical embodiment, the ultrasound transducer head can be designed as a rotary shaft which carries several peripherally arranged, individual transducer elements, where the individual transducer elements are enabled or disabled in successive, cyclic intervals during shaft rotation. Finally, in a third alternative, an electro-magnetic drive mechanism may be used, which operates according to the principles of moving coil three-phase current, ac motors. Accordingly with the last mentioned drive method, controllable forces are generated via electro-dynamic fields, which influence the rotatable ultrasound transducer head.
As already mentioned, the developmental trend in the field of of ultrasound scanners is directed toward the creation of small and easily operable applicators. However, technical solutions applied in prior art applicators include adverse effects such as forces of inertia which occur within the applicator during mechanical operations of the ultrasound transducer head. Efforts have been made to compensate for these forces of inertia with clockwise and counterclockwise operating motors. However, prior art solutions remain unsatisfactory insofar as each ultrasound transducer head is operated with a specific ultrasound frequency. Generally the entire applicator has to be exchanged in order to be able to use different frequencies.